1. Field of the Invention
The present invention pertains to procedures for cardiac revascularization and related tools for forming a blood flow path through a heart wall from a heart chamber to a coronary vessel. More particularly, this invention pertains to a tool to assist in penetrating a heart wall at an angle selected to insure axial alignment of a transmyocardial implant within a coronary vessel.
2. Description of the Prior Art
Commonly assigned U.S. Pat. No. 5,755,682 dated May 26, 1998 and commonly assigned and co-pending U.S. patent application Ser. No. 08/882,397 filed Jun. 25, 1997, entitled "Method and Apparatus for Performing Coronary Bypass Surgery", and filed in the name of inventors Mark B. Knudson and William L. Giese, teach an implant for defining a blood flow conduit directly from a chamber of the heart to a lumen of a coronary vessel. The text of the '397 application has been published on Feb. 25, 1998 in corresponding UK Patent Application GB 2 316 322 A. An embodiment disclosed in the aforementioned patent and application teaches an L-shaped implant in the form of a rigid conduit. The conduit has one leg sized to be received within a lumen of a coronary artery and a second leg sized to pass through the myocardium and extend into the left ventricle of the heart. As disclosed in the above-referenced patent and application, the conduit is rigid and remains open for blood flow to pass through the conduit during both systole and diastole. The conduit penetrates into the left ventricle in order to prevent tissue growth and occlusions over an opening of the conduit.
Commonly assigned and co-pending U.S. patent application Ser. No. 08/944,313 filed Oct. 6, 1997, entitled "Transmyocardial Implant", and filed in the name of inventors Katherine S. Tweden, Guy P. Vanney and Thomas L. Odland, teaches an implant such as that shown in the aforementioned '682 patent and '397 application with an enhanced fixation structure. One embodiment of the enhanced fixation structure includes a fabric surrounding at least a portion of the conduit to facilitate tissue growth on the exterior of the implant.
Implants such as those shown in the aforementioned patent and applications include a portion to be placed within a coronary vessel and a portion to be placed within the myocardium. When placing an implant in the myocardium, a hole is formed through the heart wall into the left ventricle. Commonly assigned and co-pending U.S. patent application Ser. No. 09/063,160 filed Apr. 20, 1998, entitled "Transmyocardial Implant Procedure and Tools", and filed in the name of inventors Guy P. Vanney, Thomas L. Odland and Eric E. Solien teaches a procedure and related tools for placement of an implant in a myocardium and coronary vessel.
When placing a transmyocardial implant, it is desirable that the implant be axially aligned with a coronary vessel following such implantation. The present invention is directed to a tool for assisting in achieving such alignment.